Seating portions of vehicle seats are required to have a large elastic stroke for satisfactory seating comfort, and a reduced thickness for both reduced weight and space saving. In some examples of seating portion structures that can achieve both such an elastic stroke and a reduced thickness, a seat cushion receiving member that extends two-dimensionally is stretched across a seat frame via coil springs or by providing the seat cushion receiving member itself with elasticity, and a seat cushion is placed on the seat frame and the seat cushion receiving member. A large elastic stroke can be implemented by the seat cushion receiving member and the seat cushion, and a reduced thickness can be implemented because a thin seat cushion receiving member and a relatively thin seat cushion can be used.
Patent Literature 1 uses an elastic sheet such as a vinyl chloride sheet as a seat cushion receiving member. Patent Literature 2 uses wires as a seat cushion receiving member, and the wires are stretched across a seat frame via coil springs. S-shaped springs are also used as a seat cushion receiving member. Patent Literature 3 also uses wires as a seat cushion receiving member, and the wires are stretched across a seat frame via coil springs.